Gear 4 Incorrect Ratio

What it means

While fourth gear was commanded, the transmission computer found that the ratio between input and output speed does not match fourth gear. It usually shows up on the highway as engine speed rising without a gain in road speed, from a slipping clutch or band that applies this gear or low pressure.

Related codes: P0730P0733P0735P0783P0741P0868

Symptoms4

• Engine speed rising on the highway without a matching gain in speed.
• Sudden engine speed flare on the 3-4 shift.
• Transmission refusing to shift into fourth or dropping out of it.
• Check engine light on and higher fuel consumption.

Possible causes5

• Low or degraded transmission fluid.
• A faulty solenoid that controls fourth gear.
• A valve body fault or a leak in the fourth gear circuit.
• Worn clutch or band that applies fourth gear, depending on design.
• Damaged internal seals for this clutch.

How to diagnose5

1. Check the fluid level and condition.
2. Watch input and output speed in fourth gear at steady cruise and under light acceleration.
3. Separate fourth gear slipping from torque converter clutch slipping by watching the difference between engine speed and input speed.
4. Read solenoid and shift codes such as P0783, and test the solenoids with a scan tool.
5. Have a hydraulic pressure test done in fourth gear.

How to fix5

1. Correct the fluid level, or change the fluid and filter.
2. Replace the faulty solenoid.
3. Repair or replace the valve body.
4. Repair the clutch or band that applies fourth gear, along with its seals.
5. Clear the codes and confirm steady engine speed in fourth gear on the highway.

The cost is low when fluid or a solenoid is the cause, and much higher when the transmission must be opened to repair the internal clutch or band.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

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